diff --git a/lib/ext/Syncroton/Backend/SyncState.php b/lib/ext/Syncroton/Backend/SyncState.php
--- a/lib/ext/Syncroton/Backend/SyncState.php
+++ b/lib/ext/Syncroton/Backend/SyncState.php
@@ -174,16 +174,7 @@
         
         // found more recent synckey => the last sync repsone got not received by the client
         if ($moreRecentStateData !== false) {
-            // undelete entries marked as deleted in Syncroton_content table
-            $this->_db->update($this->_tablePrefix . 'content', array(
-                'is_deleted'  => 0,
-            ), array(
-                'device_id = ?'        => $deviceId,
-                'folder_id = ?'        => $folderId,
-                'creation_synckey = ?' => $state->counter,
-                'is_deleted = ?'       => 1
-            ));
-            
+            return false;
         } else {
             // finally delete all entries marked for removal in Syncroton_content table    
             $this->_db->delete($this->_tablePrefix . 'content', array(